TOPIC: Network configuration

we are having an internet connection from an ISP and the traffic flow is as below

cisco 3662 --- pix515-- summit48 switch---LAN

we have pix to pix IPSEC connection to our corportate office in US.
and we have extra cisco 2621 router and pix515.

at present we are expecting a new customer and we would like to have separate isolated LAN for the new customer and this LAN users can only access email server and printserver from the existing old LAN.

could any one let me know what will be best solution for the above setup.. whether to go for subnetting or vlans..

Cisco3662
pix515
48portswitch---LAN-->-printsrv+email srv
........................(ignore these dots)........
New LAN for new customer
^
should access print and
mail of old lan and internet
from 3662 router